<html> <head> <meta http-equiv="centent-type" content="text/html; charset=utf-8"/> <script language="JavaS?1?ript"> <!-- function func(){ if (select1.value == 'val1'){ text1.style.display = 'none'; } else{ text1.style.display = 'block'; } } //--> </script> </head> <body> <select id="select1" onchange="func();"> <option value='val1'>Первый вариант <option value='val2'>Второй вариант </select> <br/> <input type="text" id="text1"> </body> </html>